MINERAL OIL PARAFFINS IN JUTE BAGS AND COCOA BUTTER

Jute bags and cocoa butter (CB) were analysed by gas chromatography (GC-FID/MS) to detect and quantify mineral oil saturated hydrocarbons (MOSH). Extraction clean-up on silica gel SPE (10 g/60 ml) was developed, as a unique sample preparation step for the determination of linear and branched n-alkanes in the range C-14 to C-31. The size of CB sample (500 mg) was sufficient for the detection of batching oil at levels of 2 mg kg(-1), with satisfactory recovery and repeatability. MOSH from batching oil form a hump of unresolved components and the shape reflect balanced molecular-mass distribution between even and odd carbon atoms (from C-14 to C-22 n-alkanes), expressed with the Carbon Preference Index (CPI=Sigma odd homologs/Sigma even homologs). Contaminated raw CB extracted from cocoa beans, transported and stored in jute bags during 2000 and 2001, showed MOSH (average 42 mg kg(-1)). However, only the 7.5% of the samples analysed of deodorized CB from 2007 to 2009 contained MOSH <36 mg kg(-1). High CPI values (>1.26) were attributed to natural hydrocarbons with a strong predominance of odd-numbered paraffins, situated between C-22 and C-31 n-alkanes (average 31.7 +/- 5.37 mg kg(-1)). The results confirmed that MOSH components below n-C-20 were fully eliminated by the deodorization process.